Here's a breakdown of the 12 races where two Trump-aligned outside groups are planning to spend a combined $12.5 million after Labor Day.

Why it matters: This is the first round of planned spending from the two GOP groups, and it shows which races Republicans are most worried about heading into November.

Between the lines: All of these races are places where Trump won in 2016. Both Minnesota races are open seats, which are historically easier to flip.

• The most surprising investment is the nearly $1 million in North Carolina's 13th district, because it's favorable to Republicans and held by GOP Rep. Ted Budd. He's been out-raised by his Democratic challenger.
• Another outside group, the Congressional Leadership Fund, is investing heavily in 25 races — only 5 of which overlap with American First Action.
• The money will be spent on TV, digital, and radio ads.

"These are not easy races," Brian Walsh, president of America First Action, said in a statement. "They represent some of the most difficult in the nation." But the groups hope their financial investment will help Republicans hold the House and expand their majority in the Senate.